There was a bug in SW 2007 that was supposed to be fixed in a later SP of 2009. I don't know if this is related to the bug. The bug: if a sheet format of the same name is being reloaded from a different location, it will not reload.

If the problem is not related, I think it is OK for your button to be gray since all you need to do to reload a different sheet format is this: select it and click OK.